[Show abstract][Hide abstract] ABSTRACT: We report for the first time that expression of the novel IL-1 cytokine receptor IL-1Rrp2 (IL-1R6) is unique to DCs within the human myelomonocytic lineage. IL-1Rrp2 was expressed by monocyte-derived dendritic cells (MDDCs) which was dose-dependently increased by IL-4 and correlated with increased numbers of differentiated MDDCs. Human plasmacytoid DCs also express IL-1Rrp2 but the receptor is not expressed by either myeloid DC type 1 (mDC1) or mDC2 cells. We also show that IL-1F8 or IL-1F9 cytokines, which signal through IL-1Rrp2, induce maturation of MDDCs, as measured by increased expression of HLA-DR and CD83 and decreased expression of CD1a. Furthermore, IL-1F8 stimulated increased CD40 and CD80 expression and IL-18 and IL-12 p70 production by MDDCs, which induced proliferation of IFN-γ-producing CD3(+) lymphocytes (indicative of inflammatory Th1 subsets). IL-1F8 and IL-1F2 were equipotent in their ability to stimulate IL-18 secretion from MDDCs but IL-1F8 was not as potent as IL-1F2 in stimulating secretion of IL-12p70 from MDDCs or inducing lymphocyte proliferation Therefore, IL-1Rrp2 expression by some DC subsets may have an important function in the human immune response in vivo via its role in differentiation of inflammatory Th1 lymphocytes.
European Journal of Immunology 12/2011; 42(3):607-17. · 4.97 Impact Factor